Telephone local-call instrument



(No Model.) 2 Sheets-Sheet 1.

' W. NICHOLS.

TELEPHONE LOCAL CALL INSTRUMENT.

e ted Aug. 14, 1883 MENTOR wzeem may! Attorney u. PETERS. Halal-WWI:Wnbinglnn. a. c.

2 Sheets Sheet No Model.)

' W. NICHOLS.

TELEPHONE LOCAL CALL INSTRUMENT.

Patented Aug. 14, 1883 llll l.

N4 PETERS. mutm m aer. Wmiw n. c.

UNITED 'STATEs PATENT OFFICE,

ILL-TAM NICHOLS, OF BOSTON, MASSACHUSETTS.

TELEPHONE LOCAL-CALL INSTRUMENT.

SPECIFICATION forming part of Letters Patent No. 283,354, dated August14, 1883.

Application filed October 14, 1882. (No model.)

To ail-whom it may concern:

Be it known that I, XVILLL M NIcnoLs, of Boston, Suffolk county,Massachusetts, have invented a new and useful Improvement in Switchesfor Telephonic Circuits, of which the following description, inconnection with the accompanying drawings, is a specification.

My invention has for its obj ectto secure secrecy, safety, simplicity,and celerity in communication between subscribers on the sametelephone-line, or different lines temporarily in circuit. It applies tothat class, of stationinstruments forming a series in which a movableswitch is an element in the connections, making a telephone a part ofthe circuit.

7 It consists in a stop operated to hold such a switch from moving outof connection in re.- sponse to any agency actuating correspondingswitches in the instruments of the series when ever subscribers on thesame line or on different lines are to be kept in communication witheach other, the cutout.

It also consists in an automatic switch and a single connection by whicha telephone is put in circuit only when a movable switch rests on thelocal switch or bell-shunt of an instrument in a series.

.l'n carrying out my improvement I have used it in connection with thelocal-call instrument for telephone-lines described in Patents Nos.235,058 and 265,454, issued to James I Stabler November 30, 1880, andOctober 3, 1882, respectively, and so much of the same as is necessaryto illustrate my invention is figured in the accompanying drawings. Thelines and connections, so far as concerns the first part of myinvention, are the same as shown and described in said patents, andreference is hereby made to said patents for details of construction notnecessary to be specified herein. 9

lnthe patents referred to each instrument in the series has a dial,index, two electromagnets with helices wound in opposite directions,between which vibrates a polarized armature carrying a standard withpawls operating a ratchet-wheel on the axis of themdex. The dial has aconductor-rim cut away opposite a unison-shunt and a local bell-shunt ineach instrument. The unison-shunt: is located alike in each instrument.The local or telephones of the rest being" bell shunt is locatedaccordingto the position of the particular instrument in the series. Theindex sweeps over the rim and interposed shunts, is always in thecircuit, and is actuated by means exclusively under the control of theoperator at the central oflice. A to-and-fro current sent from thecentral oflice over the line through the motor-magnets causes thevibrating-armature to move the index in each instrument synchronouslywith those of the others in the series. The operator, either manually orby c n automatic device at the central office, grounds the current andhalts the index in its revolution at any desired point.

The index extending beyond the rim of the dial, a detent-arm mounted onthe vibrating armature of an electro-magnet normally intervenes in itspath at a unison-point'located alike in each instrument. Theunison-shunt has an electrical connection with this detent-magnet. Thelocal shuntconnects with the bell-magnet. The current which actuates theindex has not strength to affect the detent-magnet or the bellmagnet,but if the index be on the unisonshunt or on a local shunt, theoperator, by applying a special electric instrumentality, can send overthe line a current of greater strength and of a single polarity, whichacts to draw aside the detent and release the index of each instrument,or to sound the bell of a particular instrument, as the case may be.

The rim and shunts being alternately in the linecircuit, the-deviceoutlined above, and as covered by Patent No. 235,058, enables theoperator to bring the indexes of all the instru ments in the line intounison to move and stop them together, to sound the bellcall of anyinstrument, and to out out the bells of the rest. The arrangement ofthis device, however, permitted' conversation between two persons to beheard and interrupted by the voluntary act of others, and gave no visualnotice of theline IOU cording as the index rests on the one or the otherof these shunts. This makes it possible, when two persons on differentlines are talking, to secure the same privacy ofcommunication to thoseon combinationdines that is e11- joyed by subscribers having individualconnection with the main office. The indexes of all the instruments arenormally kept at the unison-point when the line is not in use,constituting a visible signal. By a connection with the unison-shunt,when the receiver is 011 its hooklever, a subscriber can put thegenerator of his instrument in circuit and send a current over the lineto drop the annunciator By the telephone-connection with theunison-shunt, on removing the receiver, he communicates his instructionsto call a person on another line to the operator.

The latter moves the index of the subscriber s instrument upon its localshunt, and after a like operation on the proper instrument on the otherline sounds the bell of the person to be called.

shunts the telephones of these two instruments are put in circuit. Thetelephones, bells, and generators of the other instruments on the twolines are cut out. Onthe other hand, after notifying asubscriber thatanother 011 the same line desires to communicate'with him, it is.necessary for the operator first to bring all the indexes to theunison-point, then to release the detents in order to advance theindexes the distance of one station upon an extension of theunisoirshunt, or on a shunt located alike in each instrument and havingan automatic connection with the telephone when the receiver is removedfrom its hook. This provides visual notice of the line being in use toprevent unwitting"overhearing or interruption, but avails nothingagainst willful intermeddling, and secures no secrecy.

Figure l of the accompanying drawings shows a front elevation of anapplication of my invention to the local-call instrument, the operationof which has just been explained. Fig. 2 shows aside elevation. topplanview. Fig. 4 shows a modified form of the same and certain detailsof construction.

Fig. 5 is a diagram of the circuits of Fig. 1'

simplification of the connections of the unisonshunt given in Fig. 5,which constitutes the second part of my invention.

D represents the dial; 1, the index-switch;

but striking against the contact-spring z when By their connections withthe local Fig. 3 shows a' the hook-lever is-elevated, thereby closingthe primary circuit of the transmitter, with which 2 and z are connectedby wires q and q, re-

spectively; q, the secondary circuit through '1), the wire fromconductor-rim R to contactspring 0 and line 0,- p, the wire from unisonI shunt U to the detent-magnet T and switchspring k,- t, the wire fromswitch-spring 7c to the generator-frame, contact-spring c, and line 0;u, the wire from local shunt L'to contactspring 9; I 'U, the wire fromswitch-spring h to contact-spring b and bell-magnet V; r, the directconnection between the detent-magnet and generator in place of theconnection by wire 1", hook-lever, switch-spring k, and wire t. Theother letters are the same as those indicating like parts in Patent No.265,454.

Referring to Figs. 1 and 5, the current comes infrom theline m byway ofthe motor-magnets B O and axis K to the index I, which is always in thecircuit. The conductor-rim R is cut away opposite the unison-shunt U andlocal bell-shunt L. WVhen the receiver hangs upon its hook, it throwsdown the pivoted. hooklever H upon the switch-spring k. If the index beon the unison-shunt U, the current hook-lever H, switch-spring 75', wire25, gener ator-frame, continuation of wire 1, and contactspring 6 to.line 0. A subscriber can put the generator of his instrument in thiscircuit to call the central-office operator. If the index be on the rimR, the current is short-circuiiezl, passing by the wire 12 tocontact-spring c, and line 0. If the index be on the local-shunt L, thecurrentpasses by wire a to contact-spring g, switclrspring h, wire '0,contact-spring b, bell-magnet V, and contact-spring o to line 0.

The rim, unison, and local shunts being alternately in circuit,according to the position of the index, the operator sends from thecentral office a current of a single polarity and of a greater strengththan the to-and-fro current used to move the index, which, through theconnections above set forth, acts through the magnet T to operate thedetent Q, to release the index synchronously in each instrument of theseries, or to sound the bell in any desired instrument, according as theindex rests on the unison or on the local shunt. A to-and-fro current,too weak to effect the dc tent-magnet or bell-magnet, sent over the linefrom the. central office causes the armature A to vibrate between themotor-magnets. B O, and, by means of the standard F, pawls E E,ratchet-wheel G, and axisK, to move the index synchronously with thoseof the other instruments of the series, over the dial-rim and interposedshunts, it being halted upon its local shunt at the will of the operatorby grounding the current at the central ofiice,

IIO

while the indexes of the other instruments are halted at correspondingpoints on their dialrims.

A double connection with the unison-shunt and the local shunt, when thereceiver is taken from its hook, puts the telephone in each instrumentin circuit,according as the index rests upon one or the other of theseshunts. This double connection and its action are as follows: \Vhen thereceiver TV is removed, the hook-lever H is raised by its spring 5 tobreak contact with switch-spring k and make contact with switch-springs, which connects with the telephone. The lever at the same time acts to.throw up the contact-spring 51',

causing it to break contact with switch-spring h and make contact withswitch spring i, which connects with the telephone. If the index be onthe local shunt L, the current passes thence by the wire n,contact-spring g, and switchsprin'g i to the telephone. 'If the index beon the rim, neither thetelephone nor the generator can be put incircuit.

Passing now to the features constituting the first part of my inventionIn Fig. 1, S is an arm or stop pivoted upon the frame M of themotor-magnets B C and moving in a plane at right angles with that of themovement of the hook-lever H,- on which a receiver, W, is indicated ashanging; When the receiver is removed from its hook, the lever is thrownup by the spring 2:, in consequence of which. the inclined stud O of thehook-lever (shown in Figs. 1 and 2) throws forward the lower extremityof the arm S to rotate the latter on its pivot. This, as shown in Fig.3, operates to cause the upper extremity of the arm or stop'to intervenein the path of the pin P, {shownin Fig. 4,) inserted in the anteriorface of the ratchet-wheel G on the axis K of the index I. I

The ratchet-wheel and pin are adjusted to each instrumentwith relationto the point at which the index in its movement over the dial rim Rencounters thelocal shunt L.

The spring attached to the frame, throws the stop out of engagement withthe pin whenever the hook-lever is depressed by the restoration of thereceiver to its hook.

By the telephone-connection with the union shunt, on removing thereceiver, a subscriber communicates his instructions to call another onthe same line to the operator. The latter moves the index of the properinstrument upon its local shunt, and sounds the bell of the person to becalled. In so doing he moves all the other indexes in the'h'ne to acorrespond ing point on their dial-rims, except that of the firstsubscriber. The automatic operation of the stop on the receiver, beingremoved from its hook, arrests this index in its passage over its localshunt. By their connections with the local shunts the telephones ofthese two instruments are put in circuit. The telephones, generators,and bells of the other instruments on the line are cut out.

Instead of the arm or stop S being pivoted upon the frame M, as shown inFigs. 1 and2, it may be fixed, as shown in Fig. 4, to the hooklever, andof such a shape as to be thrown up in the path of the pin P when thelever is raised on the removal of the receiver.

In the foregoing applications of my invention to the localcallinstrument previously described the electrical connections are the sameas those set forth in Patent No. 265,454.

It is evident that a stop operated manually.

through the exterior case of the instrument may be made to intervene inthe path of the index; but this method has obvious objections which donot pertain to the automatic stops above described. A stop pivoted onthe frame M and operated by the hook-lever may be also made to engagedirectly'with the index, and various equivalents to effect the sameobject as the preferred methods already given will suggest themselves tomechanical minds.

Among subscribers on the same line it will be seen that the improvementset forth above secures secrecy of communication between particularpersons by cutting out the telephones of the others, safety frominterruption by cutting out the other generators, simplicity ofconstruct-ion by doing away with the need for an extension of theunison-shunt or the establishment of a special conversation and sig nalshunt, and celerity of operation by dispensing with three maneuveis onthe part of the central-office operator.

Another feature of my invention provides a simplification of theelectrical connections described above and shown in Patent No. 265, 454.In place of the double connection of the tele phone with theunison-shunt and local shunt in each instrument in the series, a singleconnection with the local shunt is substituted.

The connection between the unison-shunt and detent magnet with thehook-lever and alter ate connections with the switch-spring It and thegenerator-frame and with the switch-spring s and the telephone aredispensed with. The local shunt L connects with the contactspring g bythe wire a. The switch-spring h connects with the bell-magnet by thewire 1;, and the switch-spring 71 connects with the telephone.

When the receiver XV hangs upon its hook and depresses the pivotedhook-lever H, the contact-spring g rests upon the switchspring h. henthe receiver is removed, the lever rises and throws up the spring 9against the switch spring i.

p In place of the connection between the detent-magnet and thegenerator-frame by the wire r, hook-lever, switch-spring k, and wire it,a direct connection. by the wire '2" is substituted.

The current comes in from the line m by way of the motor-magnets B C tothe index I. If the index be on the unisonshunt U, (see Fig. 6,) thecurrent passes by the wire '2', detent-magnet T, and wire r to thegenerator,

ceiver WV is removed and the lever elevated,

the contact between 9' and h is broken, and then the current goes by wayof the switchspring 4/ to the telephone, and thence by wire (1 to line0.

The operation of this form of my improve-- ment is as follows: Asubscriber, by the con the central office, and removesthe receiver fromits hook. The operator, on receiving the call, moves the indexes of theother instru ments on the line through one revolution, the subscribersindex being arrested on its local shunt and his telephone put incircuit. The subscriber then communicates his instructions to callanother on the same line to the opera tor,-who moves the index of theproper instrument upon its local shunt and sounds the bell of the personto be called. If the instructions are to call another person on adifferent line, he performs a like operation on the proper in.- strumenton that line after moving the indexes on the first line from theunison-point. In either case by their connections with the local shuntsthe telephones of these two instruments are put in circuit. Thetelephones, bells, and generators of the otherinstruments on the sameline or on the two lines are cut out.

NVhile the device has been shown in its particular application to theinstrument covered by the patents referred to, it will be seen that itmay be adapted to various apparatus of a similar character, and that theinvention is applicable to all instruments having the general mode ofaction above specified.

The present invention is restricted to-those matters and things whichareclaimed herein, and as to all features, devices, or combinationswhich are shown or described, but not claimed, the right is reserved tomake the same the subject of a separate application.

Having thus described the nature, construction, and operation of myinvention, what I claim as new, and desire to secure by Letters Patent,is- I 1. In a local-call instrument for telephonic purposes, anelectricallyractuated switch connecting the telephone with the line, incombination with a stop for said switch, operated independently of theelectric influence to maintain the switch in connection, substantiallyas described and shown, whereby connectionbe tween two instruments maybe positively main= tained at will.

2. In a local-call instrument for telephonic purposes, a rotary indexwhereby the instrument is placed in and out of circuit, and electrically actuated devices, substantially as shown, for moving saidindex, eombined with a stop mechanism, substantially as described,independent of the electric influence, to arrest the movement of theindex and hold the same in electric connection, whereby theinstrument'may be maintained in circuit, notwithstanding the tendency ofthe electric current to move the index.

3. In a telephonic exchange system, a localcall instrument containing arevolving index, whereby the telephone is placed in and out of circuit,combined with a stop device for said index, and means, substantially asdescribed, whereby the stop is thrown into and out of action by theremoval or replacement'of the receiving-instrument.

4c. In atelephonic exchange system wherein a series'of individualsubscribers call-instruments are connected with a central station, thecombination, in such instrument, of a moving index electrically actuatedfrom the central office, and serving to place the telephone in and outof circuit, a hook-lever whereby the receiving-instrument is thrown intoand out of connection, and a stop device actuated by said lever toarrestthe movement of the index, whereby the telephone may be positivelyretained in circuit.

5. In atelephonic exchange system, the combination, with the main line,of a series of local-call instruments, each instrument con taining anelectricallyactuated switch operat ing at a different timefrom likeswitches in the other instruments, -to establish a connection withthemain line, combined with a mechanical stop device therefor,substantially as described, whereby the switch in any of the series maybeheld mechanically and positivelyin connection, and thus thecorresponding instru ment maintained in circuit indefinitely.

6. In a telephonic exchange system, the combination, with themain line,of a series of local-call instruments, each embracing the followingelements: the electrically actuatedmain-line switch, closing at adifferent time from the like switchesin the otherinstruments of theseries, the local shunt, the telephone con necting with the main linesolely by said switch and shunt, and the stop devices, substantially asdescribed, for the main-line switch, operating independently of the stopdevice in the other instruments and of the electric influence, wherebyeither instrument of the series may be maintained in circuit at will.

7. In a local-call instrument for telephonic purposes, theelectrically-actuated rotary in-' dex, whereby the instrument is placedin and out of circuit, combined with a manual stop device, substantiallyas described, to arrest the motion of said index and hold the instrumentin circuit, whereby communication between two parties maybe maintainedat will.

8. -Ina telephone local-call instrument, a

movable switch in the line-circuit, a local-station shunt,acontactspring, g', in connection with said shunt, combined with itpivoted lever whereon the receiver may behung, 2% switchspring, i, andastop device toarrest the motion cf the main-line switch at a givenpoint, substantially as described, whereby the telephone may bemaintained in circuit through the medium of 2t single connection atwill;

-9. In a local-cell instrument such as described the combination of theunis0nshunt, wire 1-, detent-maignet, T, and Wire a", leadingdircctlyifrom said magnetto'the generator.

10. In a telephonic exchange system, the

combination, with the main line, of a series of I 5 10ca1- cellinstruments containing synchroncuslycperating switches connectingthesame with the main line, combined with stop-devices for saidswitches, located one in each instrument, and arranged as described, tooperateindependent of the electric influence, whereby either instrumentmay he held in circuit independently of the action of the others:

WILLIAM NICHOLS.

Witnesses: I

PHILIP T. DODGE, CHAS. F. MYEns.

